downconvert_init

Calling sequence

dn = downconvert_init(nu)dn = downconvert_init(nu, opt)

Parameters

nu:

Normalized RF or IF frequency (between -0.5 and 0.5)

opt:

'r' (default) for real input signal, 'c' for complex input signal

Description

If the input signal is complex, no image filtering is down.
If the input signal is real, image is removed with a low-pass filter
with cut-off frequency set to if , and otherwise
(in either case, half-way between baseband signal and image signal).